The present invention relates to water pipes, of the bong or toker type, and particularly to a bowl therefor.
Such pipes include, as the central component, a vessel provided with two openings arranged to be filled with water to a level such that the water blocks the path between the two openings. One opening is provided with a tube formed to receive a bowl for holding the smoking substance, while the other opening forms a passage with which the smoker's mouth is to communicate. The outlet end of this passage may have a large diameter and be shaped to surround the smoker's mouth, or may have the form of an ordinary mouthpiece. Either one of the openings is usually at the top of the vessel, while the other is usually located in the vessel side wall.
The bowl for holding the smoking substance normally has a small hole, typically of the order of one-eighth inch diameter, at its bottom for the passage of air and smoke, as well as ashes. This hole is dimensioned to support a charge of smoking substance and regularly becomes clogged, requiring use of a poker of one type or another for clearing the hole. Moreover, when a charge of smoking substance has been used up, the remaining ashes, unburned material and residues must be cleared out, either by pushing it through the hole or by dumping or scraping it out of the bowl.
In addition, it is generally considered desirable to have the water in the vessel at a low temperature in order to cool, and thereby smooth, the smoke. Therefore, efforts are made to cause the thermal conductivity of the vessel to be as high as possible so that any tendency of the water to become heated will be opposed by heat conduction through the vessel walls.